The present invention relates to the packing of cigarettes or the like, and more particularly to improvements in a machine for confining blocks or groups of cigarettes, cigars, cigarillos or analogous rod-shaped smokers' products in one or more envelopes which may constitute soft or flip-top packs.
It is already known to pack blocks of cigarettes in a machine wherein the blocks are fed seriatim into a first portion of a predetermined path, blanks for the making of envelopes are fed into a second portion of the same path, and blanks for the making of additional envelopes are fed into a third portion of the same path if each pack includes more than one envelope. The blocks and the associated blanks are thereupon moved together whereby the blanks undergo a series of deforming treatments to be converted into envelopes each of which has an open end. The assemblies of blocks and envelopes are thereupon transferred into a second path wherein the open ends of envelopes are closed. It is also known to monitor the first path for the presence or absence of blocks and to admit a blank only when the thus admitted blank is certain to be assembled with a block. Reference may be had to the commonly owned U.S. Pat. No. 3,750,676 to Kruse et al or to the commonly owned German Offenlegungs schrift No. 2,049,984.
The patent to Kruse et al further discloses a machine wherein empty packs (each having an open end) are assembled during travel of blanks along a first path and the empty packs are thereupon transferred into a second path only if they are certain to receive blocks of cigarettes. The blocks are fed by a compacting conveyor which receives blocks from a block forming device. The transfer of an empty pack from the first into the second path is prevented if the pack is incomplete, e.g., when it consists of one instead of several envelopes. The block which was intended to be introduced into an incomplete pack is expelled from its receptacle and its components (cigarettes) are returned to the magazine of the packing machine or broken up to recover the tobacco shreds.
The just discussed machine exhibits the advantage that empty packs are not wasted and also that an empty pack cannot enter that portion of the machine wherein its presence could lead to malfunctions and eventual interruption of operation. As a rule, the making of empty packs is interrupted in automatic response to an interruption of the feed of blocks of cigarettes. The empty packs which fail to receive cigarette blocks, the blocks which are not introduced into packs, and/or the packs which failed to receive blocks due to incompleteness must be collected, the envelopes removed by hand, the thus removed envelopes discarded, and the cigarettes manually returned into the magazine of the packing machine. It has been found that such procedure invariably results in damage to a large number of cigarettes, mainly due to escape of tobacco shreds at the ends of tobacco fillers. Therefore, when a cigarette wherein the density of the end portion of the tobacco filler is unsatisfactory advances beyond the customary testing unit which monitors the heads of cigarettes in successive blocks for the quality of the ends of tobacco fillers, the corresponding block is rejected and, if its cigarettes are reintroduced into the magazine of the packing machine, the rejection can be repeated several times until the cigarettes are sufficiently deformed to be detectable with the naked eye. Furthermore, defective cigarettes in a block which has been segregated by the just discussed testing unit are likely to be divided among several blocks each of which is thereupon segregated due to defectiveness of one or more of its components.